1. Field of the Invention
The current invention relates to internal combustion engines, and, more particularly, to a supercharging unit for use with an internal combustion engine.
2. Description of the Related Art
Supercharging units for combustion engines and for combustion engines of the type specified here are known in the current state of the art. Such a supercharging unit is driven by exhaust gas flowing from the internal combustion engine and serves to compress the charging air supplied to the internal combustion engine. Two-stage supercharging units which include a high pressure and a low pressure component serve to increase the efficiency of compression and to better utilize the exhaust gas energy. A supercharging unit for an internal combustion engine is known from German patent application DE 27 52 988 A1 which features a high pressure turbine through which exhaust gas from the internal combustion engine flows and which drives a high pressure compressor causing rotational movement around a first axis. It moreover includes a low pressure turbine through which also exhaust gas flows, wherein the low pressure turbine drives a low pressure compressor for rotational movement around a second axis. The high pressure turbine and the high pressure compressor are arranged on a common shaft whose rotational axis defines the first axis. The low pressure turbine and the low pressure compressor are arranged on a second shaft whose rotational axis defines the second axis. The first and the second axis are arranged perpendicular relative to each other. Exhaust gas from the internal combustion engine flows first through the high pressure turbine and from there—viewed in flow direction—comes to the low pressure turbine. Charging air for the internal combustion engine is initially compressed by the low pressure compressor and is then supplied to the high pressure compressor for further compression. It has been shown that this arrangement requires a comparatively large space whereby also the fluidic arrangement of the two turbines and compressors relative to each other is also not ideal.